Toilet cleaning compositions dispensers of the type for placement in the tank of a flush toilet are well represented in the prior art. In one embodiment the prior art dispenser comprises a substantially enclosed vessel for containing a solid cleaning vehicle and having at least one portal for water to enter and leave and usually a portal to vent air therefrom, the dispenser resting on the bottom of the tank or being suspended within the tank and from the rim thereof. Filling of the tank subsequent a flush similarly fills a portion of the vessel, the water therein dissolving a portion of the cleaner vehicle to form a concentrated cleaning solution which is released into the tank water on the occasion of the next flush of the toilet. Dispensers of this type may further include various passageways and interior compartments to isolate by forming an air lock the concentrated cleaning solution from the tank water during the quiescent period between flushes; to delay the release of the concentrated solution into the exiting tank water, or to control dissolution of the solid cleaning vehicle.
The disadvantage with such dispeners lies in the fact that the concentrated cleaning solution formed within the dispenser is discharged into at least a portion of the tank water and thus diluted before reaching the bowl. Moreover, typically greater than 70% of the tank water passes through the bowl and into the sewer, and any cleaning vehicle actives contained therein is wasted. Accordingly, these dispensers discharge into the tank water an amount of the concentrated cleaning solution in excess of that which is actually required for cleaning.
Most if not all toilets including a flush tank further include a vertical standpipe or overflow conduit within the tank and which is connected directly with the bowl. The overflow conduit is provided to add water to the bowl after the drain valve closes and in the event the tank water rises above a predetermined level. A number of prior art devices take advantage of the tube to dispense cleaning solution into the bowl. Thus, Can. Pat. No. 1,014,702 to Bush et al and U.S. Pat. No. 4,142,260 to Snyder disclose a device adapted for insertion within the standpipe comprising an elongated tube having an upper reservoir for containing a prepared cleaning solution and a lower air chamber, there being an apertured partition therebetween, the lower end of the chamber opposite the partition being open. That portion of the refill water diverted to the standpipe flow past the lower end of the device creating a vacuum within the air chamber thereby withdrawing a dosage amount of cleaning solution from the reservoir.
U.S. Pat. No. 4,467,480 to Keller discloses a standpipe residing dispenser comprising a lower reservoir for containing a solid cleaning vehicle having an apertured bottom and an upper chamber open at the top, there being an apertured partition between said lower reservoir and said upper chamber, the upper chamber including means to support the dispenser from the top of the standpipe. Water from the auxiliary tank refill line enters the upper chamber, which is rapidly flooded, excess overflowing and running off through the standpipe to the bowl. A portion of the water entering the upper chamber enters the lower chamber and dissolves by contact a portion of the solid cleaning vehicle therein, the aqueous solution of solid cleaning vehicle being dispensed continuously through the bottom aperture. When the auxiliary water flow stops, liquid contained in the upper chamber and the lower reservoir drain off. In an alternate embodiment shown in FIG. 7 of Keller, the lower reservoir has a sealed lower end and has side wall orifices proximate its top. Incoming water flows through an aperture in the partition between the upper chamber and the reservoir and mixes with residual concentrated cleaning solution in the reservoir, a thus diluted cleaning solution exiting by way of the side wall orifices.
U.S. Pat. No. 4,229,410 to Kosti discloses a toilet element having bacteriostatic and other activity that is retained within the drain connecting the tank and the bowl, the drain being defined as including an upright drain tube through which water passes during a flush only.
U.S. Pat. No. 2,697,841 to Collins concerns a standpipe insertible device comprising an elongate tube for containing a granular cleaning vehicle having a perforated lower end and an inlet tube proximate the top for connection by a rubber sleeve to the auxiliary water supply line. U.S. Pat. No. 3,911,507 to Collins concerns a dispenser mounted external the standpipe, the dispenser comprising a container, inlet and outlet ports and a regulator valve, the auxiliary water supply line being connected to the inlet port and the outlet port including a conduit leading to the standpipe. Water entering the container displaces a like amount of cleaning solution into the standpipe.
U.S. Pat. No. 2,761,151 to Ferrando discloses a device comprising a reservoir situated above the standpipe for containing a liquid cleaning composition; an upper chamber below the reservoir including a water inlet port; a lower chamber below the upper chamber, the partition between the chambers being apertured, and spring actuated valve means connecting the reservoir to the lower chamber, the weight of water in the lower chamber opening said valve means to dispense solution.
A disadvantage of prior art dispensers is that the cleaning vehicle solution is dispensed upon the onset of auxiliary water flow and continues throughout the period during which the flush valve is open. Thus, a portion of the cleaning solution passes through the bowl. Another disadvantage is that water entering the dispenser from the auxiliary water flow line has a temperature essentially that of the water supply source as measured at a point remote from the device, typically as it enters the residence of a consumer, where it quite often is dependent upon the ambient temperature conditions. This is most typically a problem in winter and summer when water temperature extremes would greatly vary cleaning vehicle solubility. Thus, in prior art dispensers controllability of the rate of dissolution of the solid cleaning vehicle is poor.
It is an object of the present invention to provide a dispenser that resides in the overflow tube or standpipe of a toilet tank and which dispenses a predetermined quantity of active cleaning solution into the bowl water.
It is a primary object of the present invention to dispense solution to the bowl from the dispenser subsequent to the closing of the water refill valve.
It is another object herein to provide greater control over the effects of water temperature on solubility of the solid cleaning vehicle.
These and other objects and advantages of the invention will be more fully understood upon inspection of the appended drawings and reading the detailed description provided herein, a summary of which follows.